Integrated circuit (IC) packages must be tested after their manufacture, normally at elevated temperatures, which is typically a burn-in process. During that process, it is often necessary to control the temperature of ICs, sensors, and other elements. Techniques for doing so have been widely practiced for many years. The system normally consists of a heater (or cooler), a temperature sensor, and a comparator which applies energy to a heater in proportion to the difference in voltage measured on the temperature sensor as compared to a reference voltage. The energy is applied in the proper direction to cause the difference voltage to be reduced. Temperature control modules and temperature sensors of many types are widely sold for these purposes. A typical application is the control of the temperature of ICs for a burn-in process because of the temperature sensitivity of the ICs.
To achieve more accurate testing results, it is desirable to control the temperature of each individual IC being tested. Within a testing oven without individual temperature control, the actual temperature of each IC can vary due to different rates of convection, heat dissipation, or radiation within the oven. Individual temperature control can be achieved by sensing the temperature of each IC and varying the heat directed to each IC through the use of individual heaters.
Two such examples of sensing and heating individual ICs can be found in U.S. Pat. No. 5,164,661 to Jones and U.S. Pat. No. 5,911,897 to Hamilton. Both Jones and Hamilton disclose a testing socket with a sensor in direct contact with an IC that senses the temperature of the IC and a heater also in contact with the IC for affecting a change in the temperature of the IC. However, both Jones and Hamilton disclose separated sensors, heaters and controllers that require wiring to connect each sensor to a controller physically separated from the testing socket. Problems can arise during testing, caused by faulty sensors, wires, heaters or a failure of time-phasing between the controller and the sensor and heater. If any of these faults occur, the tester must check each individual component to discover the faulty component.
As shown in FIG. 10, in Hamilton, a temperature sensor 110 is positioned within an insulated sensor housing 112 such that the sensor 110 protrudes from the housing 112 to contact the integrated circuit being tested. The sensor housing 112 is located in an opening in the heat sink 114.
In both Hamilton and Jones, the temperature sensor directly contacts the integrated circuit when the socket is closed. The direct contact between the temperature sensor can cause damage to the integrated circuit because of the point loading of the relatively small temperature sensor on the integrated circuit when the socket is clamped closed. Damage to the temperature sensor can also be caused by the direct contact of the integrated circuit to the sensor.
Also, both Hamilton and Jones disclose testing sockets utilizing a threaded attachment of the heating and sensor elements to the testing socket.
Thus, it would be advantageous to have a testing socket with the sensor, heater (or cooler), and controller integrated into a single module and it would be advantageous for the testing socket to utilize a quickly releasable means to secure the module against the IC.